An atomic layer deposition method is a method for alternately supplying, on a substrate, gases of elements constituting a thin film to be formed to form the thin film on the substrate in units of atomic layers, and is known as a technology for uniformly forming a thin film.
The atomic layer deposition method is excellent in step coverage and film thickness controllability, compared to a general CVD (Chemical Vapor Deposition) method.
When formation of a thin film is repeatedly performed by the atomic layer deposition method, the thin film is adhered also on an inner surface of a film deposition chamber. When the thickness of the thin film adhered on the inner surface of the film deposition chamber is increased, the deposited thin film is peeled off, and a part of the thin film becomes particles, which causes deterioration of the quality of the thin film formed on the substrate. Therefore, the thin film adhered on the inner surface of the film deposition chamber is preferably removed regularly.
Examples of a cleaning method for a film deposition chamber include a wet etching method and a gas etching method. In the wet etching method, the thin film adhered on the inner surface of the film deposition chamber is removed by liquid such as hydrofluoric acid, for example. On the other hand, in the gas etching method, etching gas is supplied to the inside of the film deposition chamber, so that the thin film adhered on the inner surface of the film deposition chamber is removed.
Additionally, a device using an adhesion preventive plate in CVD film deposition or sputtering film deposition (refer to Patent Literature 1), and a vapor phase growth device that suppresses generation of gas from deposits deposited on an inner wall of a chamber by covering the deposits deposited on the inner wall of the chamber with an amorphous film are known (refer to Patent Literature 2).
Furthermore, a device that purges nitrogen gas into a space generated in a clearance between an injector for supplying gas and a film deposition device, to avoid film adhesion to an injector insertion hole for installing the injector is proposed (refer to Patent Literature 3).